So! I finally did it. Sinners combined with stuff from Hello Kitty Dream Village (not the Steam game - the app that used to be Hello Sweet Days). It's a gacha game just like Limbus but instead you just hang out, create a virtual avatar that represents you and - most importantly - create a room anyone can visit. You can also choose a Sanrio character to guide you during the tutorial. During its lifetime it's had several banners and events and it's covered quite some aesthetics, though not all of them. These are the ones I thought were "-core" of the particular Sinner. Explanation for each Sinner under the cut.
Yi Sang: Black/white/grey themes. Afterschool stargazing kinda reminded me of the League. Camellia bc of Dongbaek, Fox Forest bc of Sunshower. I knew that I had to add Twins Bound by the Lunar Contract because of the monochrome wings theme. I think his buddy would be Badtz-Maru, purely because he's a black bird (well, penguin).
Faust: Has a lot of the mystical themes, like the Mystical Alchemy one, the Ghost Wedding and of course the Tarot Lucky Bag. I also added Marionette for her due to her implications of not being fully independant. This whole thing was actually inspired on the latest Petit Collection (the image at the top left) which was a pink-themed one with slight lab themes that I knew belongs to her. I think her buddy would be Kuromi or the Twin Stars.
Don Quixote: Mostly vampire and amusement park themes. And yes, I know it was Ishmael who introduced us to the totally not D&D, but I just had to give this one to Don instead because otherwise there was nothing I had to represent her fantasies and adventures. I think her buddy would be Pompompurin!
Ryoushuu: This one was easy - I put most of the Japanese stuff with her, and many of them also overlapped with red and with ghosts, which was a nice bonus. Spring on the Brush (the top left one) was one I knew I had to include. I think her buddy would be Kuromi.
Meursault: He was kinda tough. The only one I had pinned down from the start was the Secret Mission with Dobermann, but the others were kind of up for grabs with the only real restriction is that it kinda had to be one of the less over the top ones. Which is very rare. I mostly ended up picking muted colors and black/white. I think his buddy would be Tuxedosam.
Hong Lu: There's so many nice Chinese stuff in this game that I could fill the entire thing with it! Even the current event is Chinese, even though I couldn't get a good square image of it yet. I think his buddy would either be Pochacco or Tuxedo Sam, or maybe even Wish Me Mell.
Heathcliff: There's two wolf ones that I had to include, since it's a part of him even though it's not a very nice part. That aside I also included Gear-Driven Artisan because of T Corp, and the others are Victorian Mansion kinda themed, or goth. I also put in the Library one to hint at his hidden intelligence. I'm not sure who his buddy would be, but I'm slightly leaning towards Kuromi.
Ishmael: This game has. So. Many. Sea. Stuff. Seriously, everytime summer comes around - and outside of that too - there seems to be some kind of ocean/sea/sealife/general marine kinda theme going on. There were so much things that I could not include, like, there's even one called "Finding Your Porpoise"! I think her buddy would be Hangyodon.
Rodya: This girl probably dreams of the luxury life with all of the good and none of the bad, so I reflected that in the high-life kinda fashion themes. I put her gambling in the Magician and the Illusionist ones (this game is supposed to be so PG that even the words "ass" and "butt" are flat out unable to be typed in the forum threads while Limbus literally flashes a list of over ten trigger warnings whenever you start the game). I think her buddy would be Hello Kitty or Kuromi.
Sinclair: His was a bit tricky, but I knew that I had to include one Christmas one in there because...well...that. I also included some school themed ones in there and the rest is mostly based on his light green color. Also, Alice in Wonderland because I just thought it fits his vibe kinda. I think his buddy would be My Melody.
Outis was another tough one. Aside from the current Sweet Collection, which is Queen of the Crimson Forest, this game hasn't done much Greek stuff yet. Emerald City is of course a stealth reference to the Oz Abnormalities and that Outis is still on a desperate journey to find home. The others are pretty much solely vibe-based. I think that funnily enough her buddy would be Wish Me Mell, idk why.
Gregor was certainly the hardest to get. Everything this game is about is kind of the opposite of his whole aesthetic. Snow White because apples, the rest kinda brown because of his color, and I just thought that the Shadow of Wandering Dreams slightly fit his restless vibe. I added Kuromi's Lab purely because of the entire Gene Corp business (remember how PG this game wants to be). I think his buddy would be Hangyodon.
I didn't include Dante - since my headcanon is that their taste is...whatever yours is in the game! Is this an excuse? Absolutely. Do I like it? Also absolutely.